In general I propose to work in the area of mammalian reproductive ecology, concentrating on the regulation of reproduction by pheromones. Specifically, I intend to continue the elaboration of a model which describes the totality of the pathways by which pheromones affect reproduction in mice. In this research I will emphasize the immature female, thereby simultaneously studying the hormonal responses to pheromones and the hormonal bases of puberty. The final stages of sexual maturation in the female mouse may take several weeks if they are housed in groups or, conversely, this state of development can be collapsed into a precise three day period if the females are paired with males. I intend to use infusion techniques to determine the blood levels of pituitary hormones which mimic the immediate actions of the male and hence, which in themselves elicit the first preovulatory surge in LH secretion. I also plan to study the hormonal antagonism of these pre-surge conditions by a female-originating odor. Furthermore, I intend to develop and use a unique experimental design which incorporates group housing vs. male-exposure to produce weight- and age-matched pairs of pre- vs. post-pubertal females. This type of comparison is not feasible with any other species now used in pubertal research. Initially I intend to use these matched groups to investigate peripubertal shifts in the sensitivity to estradiol of both the positive and the negative feedback control of LH secretion. In experiments not related to puberty, I intend to further characterize the adult male's release of LH in response to female urine. For example, I intend to study the relationship between episodic surging and the male's capacity to release LH in response to female urine. Furthermore, I will examine the relationship between the pheromonal potency of a male's urine and his exposure to female stimuli. Finally, I intend to determine the hormonal responses to pheromones in the reflexively-ovulating vole and to examine the relationship between light intensity and productivity in both wild-caught and domestic house mice.